One of the key components of realizing the promise of gene therapies is the delivery of genes encapsulated in a vector. Although both viral and non-viral vectors have been explored, the inherent transfection ability of viruses has meant that viral vectors remain the most popular choice for gene therapy applications. One large bottleneck for the large scale production of viruses needed for clinical trials and eventually treatments, however, is purification, which currently accounts for up to 70% of their production cost. Hence, new methods for fast and efficient virus purification are critically important. We propose to demonstrate the purification of viral particles using a high-efficiency nanoporous composite membrane and to demonstrate their superiority to current membranes. These nanoporous composite membranes will offer rapid processing and high purity relative to current membrane processes, thereby dramatically improving purity and reducing the amount of additional time, labor and cost intensive purification needed to achieve the vector purities that are critical for clinical application. In Phase I, we will purify a model virus from protein and DNA contaminants in its production stream, using two nanoporous composite membranes that we will prepare with pore sizes that closely bracket the size of our virus. We will compare the efficacy of this purification, in terms of both contaminant removal (protein and DNA) and virus retention to that of selected commercial membranes with similar nominal pore sizes. In Phase II, we will extend this demonstration to the adeno-associated viral vectors which currently show promise for treatments of cystic fibrosis and other diseases and whose small size makes them especially challenging to purify, and we will work with a commercial partner to integrate our membrane into a complete purification process. [unreadable] [unreadable] Public Health Relevance: As more genetic therapies move into clinical trials and eventually clinical practice, demand for purified vectors increases. As purification is a huge percentage of viral vector production cost, improvements that reduce those costs as well as increase efficiency will be able to dramatically improve vector availability, thereby speeding progress through trials and ultimately improving patient health. Membrane separations are one of the least expensive and most efficient purification processes, and improving their purification ability reduces the demands on other more costly and time consuming processes.. [unreadable] [unreadable] [unreadable]